This invention relates to power driven conveyors having a plurality of driven sections. In particular this invention relates to devices for unscrambling and singulating logs.
U.S. Pat. No. 5,257,688 to Fridlund discloses a log singulator comprising a laterally spaced series of stationary steps which are interposed between a laterally spaced series of moving steps. The moving surfaces reciprocate to urge logs from an infeed location where the logs are received in a scrambled state toward the outfeed end where the logs are delivered one at a time. Singulation is achieved by selecting the height of the steps to minimize the number of logs promoted to the next step at each cycle.
U.S. Pat. No. 5,423,417 to Redekop discloses a log singulator having laterally spaced lift arms that rotate between a plurality of laterally spaced stationary steps to promote logs from one step to the next.
U.S. Pat. No. 5,351,729 to Brisson also discloses a singulator comprising a set of laterally spaced stepped stationary plates and laterally spaced moving steps.
The foregoing arrangement of laterally spaced sections is typical of many prior art log singulators. However, because the use of laterally spaced multiple sections involves several gaps between the sections, debris tends to fall between the gaps. Such debris has the potential to interfere with the drive mechanisms for the singulator. It also represents potential wood fibre which is either wasted or requires effort to recover. In any event, such debris accumulates and requires periodic cleaning.
It is an object of this invention to provide a log singulator which minimizes the amount of debris falling through gaps in the device.
It is a further object of this invention to provide a log singulator which rapidly and effectively singulates logs.
Other objects and advantages of the invention will be appreciated by reference to the following disclosure.
The invention comprises a singulator having a series of vertically overlapping and laterally offset support surfaces which reciprocate between one another through the same vertical plane. The support surfaces are continuous across the lateral extent of the singulator. The combined surfaces have the appearance of a single broad staircase with reciprocating steps.
Alternate support surfaces are connected together so as to create two sets of support surfaces which move in unison. The two sets of support surfaces are made to reciprocate out of phase with one another by 180 xc2x0 such that when one set of surfaces is at the end of its forward stroke, the other set of surfaces is at the end of its backward stroke.
An abutment surface is provided on each support surface to promote logs toward the next support surface during forward movement of the support surface. The abutment surface preferably extends from the forward edge of the support surface with which it is associated to terminate in close proximity to the support surface next below it so as to minimize the amount of debris that can be introduced between the support surfaces or between the abutment surface and the support surface below it.
The abutment surfaces of vertically adjacent support surfaces are substantially aligned when the support surfaces are at the ends of their respective strokes.
In another of its aspects, the invention comprises unscrambling and singulating apparatus for conveying logs from a first location in which a plurality of unsingulated logs are received to a second location to which singulated logs are delivered one at a time, comprising a plurality of parallel first planar support surfaces which are successively laterally offset in relation to one another and the planes of which are successively spaced in relation to one another, and the first planar surfaces being operatively connected to one another for simultaneous movement, a plurality of parallel second planar support surfaces which are successively laterally offset in relation to one another and the planes of which are successively spaced in relation to one another, the it second planar support surfaces being operatively connected for simultaneous movement, a drive mechanism for reciprocating said first and second planar surfaces in their respective planes, such that the movement of the first planar surfaces is out of phase with the movement of the second planar surfaces by 180xc2x0, the first planar surfaces being interleaved with said second planar surfaces such that successive first and second planar surfaces vertically overlap one another and each planar surface reciprocates between the planes of the two vertically adjacent planar surfaces, and an abutment surface associated with each of the first and second planar surfaces for urging a log in the direction of movement of the planar surface.
In another of its aspects, the invention comprises such apparatus wherein the reciprocating movement of said first and second planar surfaces is such that when any one of said planar surfaces reaches the end of its forward stroke and the immediately adjacent planar surface below it is at the end of its backward stroke, the abutment surfaces associated with both support surfaces are substantially aligned with one another.
In yet another of its aspects, the invention comprises such apparatus wherein the first and second planar surfaces are mounted on at least two vertical plates and the drive means comprises means for actuating movement of said plates.
Other aspects of the invention will become apparent from the detailed description of the preferred embodiment which follows and from the claims.